Improvement of Interface in SiC Particle-Reinforced Al-Li Composite by Sol-Gel Coating Technique

This paper describes a study to investigate an improvement of the interface in SiC particle-reinforced Al-Li composite by coating the SiC particle with metallic oxide film. A coating method utilizing a sol-gel technique produced fine SiC powders covered with SiO₂, TiO₂, or ZrO₂ metallic oxide film. The film thickness was not affected by the hydrolysis time of the sol solution under a dry argon atmosphere. The average thickness of the SiO₂, TiO₂ and ZrO₂ films was about 10 nm, 8 nm and 27 nm, respectively. In metallic oxide coated SiC particle-reinforced Al-Li composite, TEM observation showed that the coating film was not damaged by fabrication processing, and that the formation of Al⁴C³ at the interface between the matrix and reinforcement was controlled by the coating film. The tensile strength and elongation of the extruded TiO₂, coated sample increased by 12% and 24%, respectively, compared with the non-coated sample.